The present invention relates to mechanical scooping tool arms such as hydraulic shovels, hydraulic rakes and the like, and more particularly to a thumb for such a scooping tool arm.
Articulated mechanical scooping tool arms are often operatively mounted to a vehicle to allow heavy or large materials to be handled. Such material handling apparatuses include hydraulic shovels, hydraulic rakes, and the like. In all these cases, a scooping tool, such as a bucket or a rake, is provided at the outer free end portion of an articulated boom, and is remotely controlled from the vehicle cab through the instrumentality of hydraulic cylinders. The scooping tool can be used to accomplish a number of different operations, one of them being to scoop up materials to transport them. For example, a bucket can be used to dig a hole in the ground, or to scoop up and lift a heavy container to carry it to a desired destination.
In the cases of vehicles equipped with a scooping tool in the form of a hydraulic shovel, it is known to operatively mount a hydraulically controlled thumb on the tool arm of the vehicle in pivotal facing register with the bucket of the hydraulic shovel, the thumb pivotally co-operating with the bucket of the hydraulic shovel to allow objects to be grasped between the bucket and the thumb, or to be pushed by the thumb into the bucket. However, the known thumbs are cumbersome when they are positioned in a stored condition away from the bucket, and their shapes are not adapted for efficiently handling materials without damaging these materials.
The present invention relates to a thumb to be mounted for relative movement on a hydraulic tool arm equipped with a pivotable scooping tool for selective co-operation between the scooping tool and said thumb, said thumb comprising a pair of generally parallel transversely spaced arcuate U-shaped lateral forks, said forks having inner ends transversely interconnected by an integral transverse coupling member having for operative coupling of said thumb to the tool arm for relative movement thereabout, and outer ends opposite said inner end, said arcuate forks defining a significantly short radius of curvature about a common axis relative to the distance between said inner and outer ends.
In one embodiment, the thumb further comprises a transverse plate integrally linking said forks at said outer ends thereof.
In one embodiment, said coupling member is a pivotal coupling member and defines a pivotal axis.
In one embodiment, said forks define a concave inner surface and a ratio L1:L2 approximately equal to 3:1 is defined on said thumb, where L1 is equal to the length between said pivotal axis and said forks outer ends, and where L2 is equal to the length between (a) a line drawn between said pivotal axis and said forks outer ends, and (b) the most distant point between said concave inner surface of said forks and said line.
In one embodiment, said forks are defined along a major part of their length starting at said outer ends, by a single radius of curvature R1, and a ratio L1:R1 approximately equal to 2:1 is defined on said thumb, where L1 is equal to the length between said pivotal axis and said forks outer ends.
The present invention also relates to a thumb assembly for use on a tool arm equipped with a scooping tool, comprising a thumb for selective co-operation with the scooping tool, said thumb comprising a pair of generally parallel U-shaped lateral forks defining an opening therebetween for engagement of the tool arm between said forks, said forks having inner ends for pivotable attachment to the tool arm and outer ends opposite said inner ends, said forks being significantly curved about a common axis for providing a hollow opening between the scooping tool and said thumb when said thumb forks outer ends engage the scooping tool and for allowing a significant portion of said thumb to be positioned beyond a surface of the tool arm which is in pivotal facing register with a scooping side of the scooping tool when said thumb is pivoted against the tool arm, said thumb assembly further comprising an actuator operatively attached to said thumb for allowing pivotal displacement of said thumb relative to the scooping tool.
The invention also relates to a thumb and scooping tool assembly for operative attachment to a tool arm, comprising:
a) a thumb, said thumb comprising a pair of generally parallel U-shaped lateral forks defining an opening therebetween for engagement of the tool arm between said forks, said forks having inner ends for attachment to the tool arm for relative movement thereabout, and outer ends opposite said inner ends, said forks being significantly curved about a common axis;
b) a scooping tool selectively co-operating with said thumb and comprising an inner end for pivotable attachment to the tool arm, an outer end opposite said inner end, and a scooping side in pivotal facing register with said thumb for grasping objects between said thumb and said scooping tool scooping side;
c) mounting means, for mounting said thumb forks inner ends and said cooping tool to the tool arm for relative movement thereabout;
d) a first actuator operatively attached to said thumb for selective motion of said thumb relative to said scooping tool and to the tool arm; and
e) a second actuator operatively attached to said scooping tool for selective motion of said scooping tool relative to said thumb and to the tool arm.
The invention further relates to a tool arm assembly comprising an elongated tool arm having an outer free end equipped with a scooping tool and a thumb, said thumb comprising a pair of generally parallel U-shaped lateral forks defining an opening therebetween, said forks having inner ends, a pivot member pivotably attaching said forks inner ends to the tool arm outer free end for pivotal movement of said thumb about a pivotal axis, and outer ends opposite said inner ends, said forks being significantly curved about a common axis, said scooping tool selectively co-operating with said thumb and comprising an inner end pivotably attached to said pivot member for pivotal motion relative to said tool arm outer free end, an outer end opposite said inner end, and a scooping side in pivotal facing register with said thumb for grasping objects between said thumb and said scooping tool scooping side, said tool arm assembly further comprising a first power actuator operatively attached to said tool arm and to said thumb for selectively pivoting said thumb relative to said scooping tool and to said tool arm, said tool arm assembly further comprising a second power actuator operatively attached to said tool arm and to said scooping tool for selectively pivoting said scooping tool relative to said thumb and to said tool arm;
wherein said pivot member enables said thumb and said scooping tool to be independently pivotable relative to one another and to said tool arm about parallel axes, and wherein said thumb is pivotable between a first limit position in which said forks outer end engages said scooping tool scooping side, and a second limit position in which said thumb is pivoted away from said scooping tool scooping side and said tool arm is embedded in said opening between said thumb forks, with a transverse hollow opening being defined between said forks and said scooping tool scooping side in said first limit position of said forks for transverse, uncompressed engagement of objects carried therein, and with a significant portion of said thumb extending beyond a surface of said tool arm that is in pivotal facing register with said scooping tool scooping side when said thumb is in said second limit position.
In one embodiment, said thumb and said scooping tool both pivot about said pivotal axis.
In one embodiment, said thumb comprises a transverse plate integrally linking said forks at said outer ends thereof, with said transverse plate being positioned, in all positions of said thumb, between said scooping tool scooping side and said surface of said tool arm that is in pivotal facing register with said scooping tool scooping side.
The invention further relates to a vehicle comprising:
a frame movable over ground;
a boom pivotably attached to said frame;
an elongated tool arm having an inner end pivotally attached to said boom and an outer free end opposite said inner end and equipped with a scooping tool and a thumb, said thumb comprising a pair of generally parallel U-shaped lateral forks defining an opening therebetween, said forks having an inner end pivotably attached to the tool arm outer free end and an outer end opposite said inner end, said forks being significantly curved about a common axis, said scooping tool selectively co-operating with said thumb and comprising an inner end pivotably attached to the tool arm outer free end, an outer end opposite said inner end, and a scooping side in pivotal facing register with said thumb for grasping objects between said thumb and said scooping tool scooping side;
a first actuator operatively attached to said tool arm and to said thumb for selectively pivoting said thumb relative to said scooping tool and to said tool arm;
a second actuator operatively attached to said tool arm and to said scooping tool for selectively pivoting said scooping tool relative to said thumb and to said tool arm;
a third actuator operatively attached to said boom and to said tool arm, for selectively pivoting said tool arm relative to said boom;
a fourth actuator operatively attached to said vehicle frame and to said boom, for selectively pivoting said boom relative to said vehicle;
wherein said thumb and said scooping tool are independently pivotable about parallel axes, and wherein said thumb is pivotable between a first limit position in which said forks outer end engages said scooping tool scooping side, and a second limit position in which said thumb is pivoted away from said scooping tool scooping side and said tool arm is embedded in said opening between said thumb forks, with a transverse hollow opening being defined between said forks and said scooping tool scooping side in said first limit position of said forks for transverse, uncompressed engagement of objects carried therein, and with a significant portion of said thumb extending beyond a surface of said tool arm that is in pivotal facing register with said scooping tool scooping side when said thumb is in said second limit position.
In one embodiment, said scooping tool is a bucket.
In one embodiment, said scooping tool is a rake.